This thesis aims to investigate how the historical opponents, the Social Democrats and the Moderates, have chosen to form municipal coalition governments, a growing phenomenon in municipalities across Sweden. The thesis is limited to the electorial periods 2018-2022 and 2022-2026 in the municipalities of Katrineholm and Linköping. How has the common policy been shaped? And can the thesis, with the help of coalition theory, provide answers as to why they entered into cooperation? The thesis draws on the latest research from the Center for Municipal Strategic Studies at Linköping University. Based on coalition theory, five themes are identified through the methodological choices of text analysis and thematic coding, which form an analytical framework. The framework serves as the basis for the analysis, where the collected empirical material is coded against each theme an municipality. The analysis shows that the empirical data, interpreted through the lens of the theoretical themes, highlights concrete connections, and the results answer the questions of the thesis. The results indicate how the common platforms have been shaped through consensus on policy issues and compromises. Expressions from the municipalities' political leaders reveal a unified communication approach toward citizens. The conclusions support previous research and provide some explanation for both the emergence and development of an S and M collaboration in each municipality. Cross-bloc coalitions challenge traditional block politics and theoretical frameworks.  The study can provide a deeper understanding of the dynamics of political coalitions at the local level, encompassing processes, strategies, and relationships that need to work together within local politics.